In a control device of a DC motor outputting assist torque for an electric power steering device, it has been conventionally known to adjust steering feeling by executing compensation control such as steering wheel return control, damper control, or friction compensation control, according to steering angle speed and vehicle speed. For example, a control device disclosed in JP2003-175850A (corresponding to US 2003/0121716) estimates steering angle speed based on voltage between terminals of a motor. The control device detects an abnormal state of terminal voltage of the motor (hereinafter, referred to as terminal voltage) based on the sum of two terminal voltages and voltage of power source. When the control device detects an abnormal state, the control device sets the steering angle speed to a fixed value and calculates a value of current of the compensation control.